In current communication networks, it is known to schedule downlink data resources in specific time slots. It is known to provide time division duplexing (TDD) separating uplink and downlink resources on the same carrier by time division multiplexing. Further it is known to provide frequency division duplexing (FDD), i.e. to provide uplink and downlink resources on different carriers.
In current specifications [3GPP TS 36.213, v.9.1.0, Section 7.1] for both FDD and TDD, the scheduling of DL data resource is always performed in the same time slot when the DL data is transmitted, as it is straightforward that when there is DL data resource, there should also exist DL control resource. However, this may not be true in future releases, e.g. for cross-carrier scheduling in carrier aggregation systems (3GPP TS 36.300, v.10.3.0).